A power tool holder is depicted in FIG. 1, indicated with reference numeral 1. Such holders 1 are previously known and may be used to fasten a power tool 6 to a support arm 9, which may be telescopic. The purpose of the combination of the arm 9 and the holder 1 is to relieve a worker from the weight and torque reaction forces from the tool when using the tool, for instance in nut running or drilling with the tool. In FIG. 1, the known holder holding an angled power tool 6 is shown. The tool head is angled at 90° to the body of the tool. FIG. 2 depicts a known holder holding a straight power tool.
Such conventional power tool holders are by themselves quite uncomplicated devices, normally comprising two clamping parts that are held together by some means that can be used to force them together when clamping the power tool.
Since the force and torque that can be exerted by the power tool may be quite high, depending on the tool used, it is important that the tool is tightly fastened in the tool holder. Should the tool move in the tool holder during use, it may be detrimental to the precision with which the tool can work, for instance the amount of torque that controllably can be delivered to a screw joint. Also, the material of the tool housing in the connection region between tool and the holder may be damaged by such movements.
The importance of a firm connection between the tool and the holder is reflected in the propensity of workers to overtighten the holder when attaching it to the tool. This overtightening may in itself lead to deformation of the housing of the tool, thus damaging vital internal parts such as the gears, motor or torque transmitter.